Device and method for detecting and withdrawing a predetermined length of yarn

ABSTRACT

The device and method disclosed employ a conduit with a bend and preferably a double bend intermediate its ends through which yarn is moved, as by currents of air from a vacuum pump; adjacent the bend or the upstream bend of the double bend a photoprojector and photoreceiver switch detect the presence of yarn at the shortturn of that yarn being drawn thereacross and interrupting the beam of light therebetween to detect a predetermined length of yarn whereupon the photoreceiver switch deactivates the means used to draw yarn through the conduit and thereby establishes a predetermined length of yarn. The device and method are usefully employed with yarn piecers and knotters to avoid excessive yarn wastage and to insure that sufficient yarn is provided to effect piecing or knotting.

United States Patent 1 Cleland, Jr. et al.

[ 51 Apr. 17, 1973 [54] DEVICE AND METHOD FOR DETECTING AND WITHDRAWING A PREDETERMINED LENGTH OF YARN [75] Inventors: Luther A. Cleland,Jr., Westminster; Albert D. Harmon, Clemson, both of SC.

[73] Assignee: Maremont Corporation, Chicago,

Ill.

[22] Filed: Oct. 20, 1971 21 App]. No.: 190,741

[52] US. Cl. ..250/219 S, 242/35.6 E [51] Int. Cl. ..B65h 69/04, GOln 21/30 [58] Field of Search ..242/35.6 E;

[56] References Cited UNITED STATES PATENTS 3,203,634 8/1965 Fiirst ..242/35.6 E

Primary Examiner-James W. Lawrence Assistant Examiner-T. N. Grigsby Att0meyDonald H. Feldman ABSTRACT The device and method disclosed employ a conduit with a bend and preferably a double bend intermediate its ends through which yarn is moved, as by currents of air from a vacuum pump; adjacent the bend or the upstream bend of the double bend a photoprojector and photoreceiver switch detect the presence of yarn at the short-turn of that yarn being drawn thereacross and interrupting the beam of light therebetween to detect a predetermined length of yarn whereupon the photoreceiver switch deactivates the means used to draw yarn through the conduit and thereby establishes a predetermined length of yarn. The device and method are usefully employed with yarn piecers and knotters to avoid excessive yarn wastage and to insure that sufficient yarn is provided to effect piecing or knotting.

10 Claims, 5 Drawing Figures DEVICE AND METHOD FOR DETECTING AND WITHDRAWING A PREDETERMINED LENGTH OF YARN BACKGROUND OF THE INVENTION purposes of this invention, yarn is defined to include elongate filamentous structures such as continuous filaments, yarn formed of staple fibers and threads and elongate bundles of a plurality of such filaments, yarns and threads which bundles form an elongate filamentous structure.

This invention is usefully employed in conjunction with processes and machines used in the processing of such elongate filamentous structures for textile and other uses. Among the machines with which the present device and method are advantageously employed one may include automatic yarn piecing apparatuses used in yarn spinning and twisting applications and knotters used in yarn and thread winding applications.

Problems common to the aforesaid yarn piecers and knotters include the withdrawal of sufficient yarn from a supply thereof to permit piecing and/or knotting to be accomplished with a minimum of yard wastage. Many piecers and knotters of the art use either vacuum and/or beating to retrieve an end of yarn from the supply which end is then grasped in some manner, either mechanically and/or by vacuum, and is drawn out to provide a sufficient length thereof for piecing or knotting with another end of yarn. Often such piecers and knotters are not provided with any device which will assure that a sufficient length of yarn has been withdrawn from the supply; for example, winders commonly are provided with beaters and vacuum tubes wherein the beating of a cop of yarn is timed, as experience dictates, so that on the average about 80 percent of the time the free end of the yarn on the cop will be dislodged therefrom and withdrawn by the vacuum tube; further, application of vacuum is timed so that if and when a free end of yarn is retrieved from the cop at least a sufficient length is withdrawn for knotting purposes. In such retrieval operations, if a free end is not dislodged from the cop, the other operations including vacuum application and mechanical operations including that of knotting proceed without the yarn leading to wasted time and other disadvantages including nonknotting; if the yarn is of a particularly bulky nature or of relatively heavy weight, although the beater may dislodge the end of yarn from its cop and the vacuum may withdraw such yarn, due to the timed nature of the application of vacuum and the bulkiness or heavy nature of the yarn, an insufficient length of yarn may be withdrawn also thus preventing knotting or providing weak knotting which later may separate providing for all manner of difficulties in subsequent processing; if the yarn is of a relatively light weight, timed vacuum withdrawal although providing for a length sufficient for knotting will also provide a length which is not only sufficient but greatly in excess of that which is needed, providing for much wastage of yarn and of preventive mechanism which are required to insure that such excessive lengths are removed in a manner such that excessive lengths do not interfere with knotting and subsequent processing. In piecers and knotters which employ yarn withdrawal devices which are solely mechanical, if the free end of yarn is not dislodged from the cop, the mechanical operations proceed without the yarn, resulting in nonpiecing or nonknotting. Also, such mechanical devices are especially prone to mechanical malfunction, providing the aforesaid undesirable results and additionally machine down-time to correct the malfunction and consequent loss of production during that period.

It is to the remedy of the foregoing problems that the present invention is directed, such being an object. This and other desirable objects of the invention will become apparent from or are inherent in the following description, explanations and the appended drawings.

SUMMARY OF THE INVENTlON In the present invention, the aforesaid difficulties and problems are now virtually eliminated by the present device and method wherein one moves yarn through a conduit having intermediate its ends a bend conduit portion at a predetermined distance from the yarn entry end of the conduit. This bend and any other bends of the conduit have what we term for the purposes of this invention a short-turn" and a long-turn path which follow the interior conduit walls around the bend, the short-turn being that portion of the wall pathway at the bend which describes is the shortest path from a point on the cross section of the conduit just preceding the bend to a point on the other cross section of the conduit just following the bend, and the long-turn being that longest pathway following the portion of the wall at the bend from the upstream cross section to the downstream cross section and is usually opposite the short-turn. Intermediate any adjacent bends in the conduit there may be linear conduit portions or substantially so, even over relatively short distances; in defining the nature of the bend one herein uses the relation of the axes of the linear portions just preceding and following the bend. For this purpose we employ, for purposes of the invention, the turnthrough" angle of the axial lines of the upstream and downstream linear portions of the conduit, wherein the turn-through angle of the bend is that angle through which the extension of the upstream axial line beyond the point of intersection of the axial lines must be rotated to be coincident with the axial line of the downstream linear portion. Thus, according to the invention, the yarn moved through the conduit is aligned adjacent to the wall at the short-turn of the upstream bend of the conduit double bend and its presence there is detected. Preferably, the conduit bend will have a turn through angle of at least 45, and in preferred embodiments using a double bend the upstream and downstream adjacent bends each will have a turnthrough angle of at least 45, since with bends having turn-through angles in excess of 45, we have found, one may more precisely sense yarn which has been aligned at the short-turn of the bend and in this manner more precisely detect a predetermined length of yarn extending from a supply and through the conduit to and past the bend therein. Most preferably, the bend or where a double bend is used each of the upstream and downstream bends should have a turn-through angle of about or substantially for we have found that with such construction one may most precisely specify, de-.

tect and predetermine the desired length of yarn, say, withdrawn from a supply thereof such as from a cop or bobbin tube.

For purposes of the invention, any means may be used to withdraw yarn from a supply thereof and move it through the conduit to and past the bend thereof, the yarn necessarily in such moving extending linearly between any adjacent short-turns of bends in the conduit and following the interior wall of the conduit in curvilinear fashion around the short-turns. This discovery by us has made possible the present invention, for in moving the yarn through the bend, the yarn in making the turn is forced against the short-turn wall thereof and wherein a double bend is used the yarn between such bends extends in linear fashion and must per force turn about the interior wall of the upstream short turn of this bend; then, by positioning a detecting and/or switch element at this short-turn one may prescribe and/or record a predetermined length of yarn within the conduit and/or extending from the point of withdrawal from a supply thereof to a prescribable distance past this bend. Thus, one may position a photoelectric switch at the short-turn or a piezo-electric device at the short-turn such that yarn abutting the wall thereof will be detected. In the withdrawal of a predetermined length of yarn, such detecting and/or switch element may deactivate the means used to withdraw yarn from the supply, according to the invention, so as to prescribe a predetermined length thereof which may be deemed desirable or necessary, such as for example in piecing or knotting operations; such length of yarn then may easily be removed from the conduit for use in such operations.

In preferred embodiments, to aid in aligning the yarn at the short-turn of the bend, we have devised a bifurcate element wherein its opposing arms collate the yarn so that it may be aligned at the apex portion thereof whereat the sensing and/or switching element may be adjacently located. In most preferred embodiments, we employ as the sensing and/or switching element a photoreceiver; therein, we also employ as an activating element a photoprojector located at the long-turn of the bend which focuses a beam of light incident upon the photoreceiver and maintains the means for moving the yarn in an activated state; when the yarn is collated and aligned at the short-turn it interrupts the light beam which causes the photoreceiverswitch to deactivate the means for moving the yarn thus stopping withdrawal of yarn from its supply and prescribing the desired predetermined length hereinbefore described.

THE DRAWINGS A fuller understanding of the device and method of invention may be had through the following description of a preferred double bend embodiment thereof when taken in conjunction with the appended drawings in which FIG. 1, in fragmentary side elevation, shows a device of the invention, the pathway of yarn therewithin and a yarn supply;

FIG. 2 is a horizontal cross section taken substantially along the line 2-2 of FIG. 1 of the double bend portion of the conduit of the invention, with underlying features in phantom lines;

FIG. 3 is a vertical cross section of the double bend portion of the conduit of the invention taken substantially along line 3-3 of FIG. 2;

FIG. 4 is an enlarged section taken substantially along line 44 of FIG. 5 showing an end view of the bifurcate yarn aligning element of the invention; and

FIG. 5, partially broken away, or fragmented and in enlarged side elevation, shows the bifurcate yarn aligning element of the invention in which it is rotated about its axis some from that shown in FIG. 3.

PREFERRED EMBODIMENT Referring to FIG. 1, a supply of yarn on a yarn package 10 supported on a textile machine (otherwise not shown) for rotation as desired in a winding-up and an unwinding direction, respectively herein clockwise and counterclockwise, comprises wraps of yarn about a cylindrical core 12, known in the art as a cop or tube, to form yarn package 10 which has a terminal end at its surface of the yarn wound about the cop. Such terminal end of the yarn so wound may have been formed as the normal terminal end on a filled package having a desired length of or weight of yarn on the cop which is prescribed for subsequent processing, or a broken or parted terminal end of yarn wherein by premature parting or breakage during processing has formed but a partially filled package on the cop and thus is less than the desired length or weight of yarn required for further processing. In the former instance, further processing may entail the joining of the terminal end with another terminal end from another cop by knotting to form a yet larger package, such as in winding operations, and in the latter circumstance, further processing would require joining the prematurely parted terminal end with another end of yarn from another supply so that a filled package of prescribed amount of yarn may be formed, this joining being made by a piecing operation. In both instances, the terminal end of yarn usually adheres to the superficial wraps of yarn on the cop.

For purposes of dislodging the terminal end from the wraps of yarn, and withdrawing yarn from the cop to provide and/or sense a predetermined length of withdrawn yarn for such purposes as knotting or piecing, the present device therefor, generally designated 14, is shown to comprise a yarn withdrawal means, which in this embodiment includes a yarn beater (shown in phantom lines and unnumbered) which strokes the surface of superficial wraps on the cop to dislodge the terminal end of yarn as package 12 is rotated in an unwinding direction such as by motor M through interconnections therewith (not shown), and as yarn is withdrawn from the package by the withdrawal means the beater is continued stroking prevents the yarn so withdrawn from back-wrapping on the package, which back-wrapping may frustrate withdrawal; a conduit having intermediate its ends a double bend, yarn length prescribing and/or detecting element, generally designated 16; an upstream conduit portion thereto 18 which leads to a further upstream nozzle portion of the conduit means 20; and which nozzle portion 20 has a mouth or entry 22 to the conduit means, which is, in this embodiment, closely adjacent the outer surface line of the superficial yarn layers on cop 12 and adjacent the beater, wherein yarn may enter entry 22 after being dislodged by the beater from package and be carried through portion 18 to and through double bend 16, and there to be detected and or prescribed in length. In this embodiment, the yarn withdrawal means also includes a vacuum pump V, actuated by a motor M, so as to draw currents of air through entry 22 and the conduit to and through a waste accumulator W to vacuum pump V; thereby, yarn is dislodged for supply 10, and a cop 12 is rotated in the unwinding direction, the yarn is drawn through entry 22 to and through double bend 16 by such air currents. It is to be noted that the yarn follows a very specific pathway, namely a linear pathway between adjacent bends in the conduit and more particularly a pathway which extends linearly between adjacent short-turns and around such turns under the aegis of the air currents which put the yarn under sufficient tension to effect such pathway.

Turning now to FIGS. 1, 2 and 3, double bend 16 has an upstream conduit portion A, an intermediate conduit portion B, the upstream bend included therebetween having a turn-through angle of about 90, and a downstream conduit portion C wherein the turnthrough angle of the downstream bend included between portion B and C also is approximately 90 and wherein portions A, B and C are substantially linear longitudinally thereof. The currents of air which move the yarn 24 through the conduit place the yarn under a small, yet a sufficient tension to make it extend in a substantially linear pathway between adjacent shortturns of respective bends in the conduit, such as between the short-turn of the bend in conduit portion 18 and the short-turn of the upstream bend in double bend 16 which is included between portions A and B; also, because of such tension, yarn 24 follows the shortturn path about such bends. It is because of this discovery that, according to the invention, one may prescribe for ones needs a predetermined length of yarn by positioning a bend at a prescribable distance from the point of withdrawal of yarn from its supply, and by fixing a detector and/or switch adjacent the short-turn of this bend, so that as yarn necessarily follows the short-turn of the bend, the detector and/or switch may be actuated thereat to detect and/or provide a predeterminable length of the yarn. Thus, one may determine where to locate the bend at which to position a detector and/or switch merely by knowing (I) the yarn length desired, (2) the spacing of the conduit entry from the yarn supply and (3) the configuration of the conduit needed for a particular apparatus such as a piecer, ,then add together (a) the distance from supply to entry of the conduit, (b) the linear distances between short-turns of adjacent bends in the conduit which occur at less than the desired yarn length, ,and then add the distances along the interior conduit wall around the short-turns; then at the desired length distance, one positions the detector and/or switch at the short-turn of a bend located at this distance, or at a specific point upstream of this distance such that, taking into consideration factors peculiar to the particular withdrawal and yarn moving means and of the yarn itself, such as the weight of yarn and thus its inertia and the rate at which yarn is moved through the conduit and the diameter and upstream configuration of the conduit and the nature of its wall such as accordian-like as shown in FIG. 1 or smooth, the yarn will be moved against the short-turn of such bend to be detected or trip the switch at the time that the yarns terminal end 26 has reached the prescribed desired length from supply thereto.

In this embodiment, a photoreceiver means R is positioned at theshort-turn of the bend included between conduit portions A and B, and a photoprojector means is positioned at the long-turn thereof so that photoprojector P may focus a beam of light diagonally across the bend to impinge upon photoreceiver R. Yarn 24 is moved through this upstream bend of the double bend 16 and forced against the short-turn thereof by the tension created by the currents of air moving it through the conduit thus to interrupt the light beam. Thereupon, photoreceiver R will actuate either a recorder or other readout device to indicate that the prescriblength of yarn has been obtained, or will deactuate motor M to stop rotation of cop 12 and package 10 and stop vacuum pump P to stop the flow of currents of air through the conduit and thereby stop the withdrawal of yarn 24 to establish the desired predetermined length of yarn 24 between the point where it leaves package 10 and its terminal end 26 within conduit portion C just beyond the aforesaid upstream short-turn.

To aid in the alignment of yarn 24 at the short-turn of the bend at which the photoreceiver, or other detecting and/or switch-type device, may be located, a bifurcate aligning and yarn collating element is positioned, an exemplarily shown in FIGS. 3, 4 and 5. The purpose of this element is to assure a more immediate aligning of yarn 24 proximal to or in otherwise actuating relationship to the detecting and/or switch device. In its simplest form, such a collating element may be a bifurcated notch in the wall at the short-turn, the sloped wall of which act as opposing yarn receiving arms to collate the yarn thereat and position and align the yarn across the apex of the notch in actuating relationship to the detecting and/or switch device. In this embodiment, the collating element 28 is in the form of a generally cylindrical member with bifurcate opposing and yarn collating arms 30A and 30B having divergent faces inwardly directed to a slot generally across a diameter of the element and of sufficient width to admit yarn therebetween faces 32 thereof; slot 32, so defined, separates divergent arms 30A and 30B and terminates at the apex 33 of such arms. Element 28, at its other end is counterbored with a hole or recess 35 of size sufficient to receive and hold the photoreceiving element R of a detecting and/or switch device, and has a central hole 34 having a diameter approximately the diameter of slot 32 communicating therewith and providing a light path between slot 32 at apex 33 and photoreceiver R within recess 35. Since the diameters of yarn to be processed may differ within a range which is well known in the art, to more precisely align a particular yarn of a specific average diameter, in this embodiment set screws 36,38 are provided set into female threaded holes 40,42 such that approximately half a diameter of the bottom face of these screws may intrude into slot 32 in parallel relation to the respective slot walls of arms 30A and 303. In this manner, yarn collated by divergent arms 30A and 308 will be aligned between the bottom surfaces of set screws 36,38 at apex 33 so as to completely cut off light which would otherwise extend from photoprojector P, across the bend, through slot 32, past apex 33 and through hole 34 and recess 35 to impinge upon photoreceptor R. Appropriate circuitry, well known to the art and otherwise not described herein, in use to connect photoreceptor or photoreceiver R with motor M so that the latter will normally be operative so long as light is received by photoreceiver R and is deactuated when light is no longer received. The yarn receiving distance between the bottoms of screws 36,38 may be adjusted by using a flat gauge with thickness of that of the yarn 24 to be processed.

We claim:

1. A device for the withdrawal of a predetermined length yarn from a supply thereof, comprising:

conduit means for establishing an enclosed, internal pathway of predetermined length for said withdrawn yarn, said means having an entry for receiving yarn from said supply, a fixed bend at a predetermined distance from said entry and a second fixed bend beyond said bend;

yarn withdrawal means for withdrawing yarn from said supply through said pathway and adjacent the short-turn of said bend; and

switch means, located at least in part within said enclosed internal pathway adjacent said short-turn, for sensing the presence of yarn thereat and deactivating said withdrawal means thereupon; wherein, said predetermined yarn pathway is established from said entry to and around said short-turn and to and around said second bend.

2. A device as in claim 1, wherein said bend and second bend are joined by a linear portion of said conduit, and have upstream and downstream thereof, respectively, conduit portions which are substantially linear, and

wherein the axes of said upstream and intermediate portions and of said intermediate and downstream portions are set at, respectively, a turn-through angle to one another of at least 45.

3. A device as in claim 2, wherein said turn-through angle of said two sets of axes is substantially 90.

4. A device as in claim 1, wherein said switch means comprises sensing and deactivating means located at the shortturn of said bend for photoelectric sensing of the presence of yarn within said bend and for deactivating said withdrawal means.

5. A device as in claim 4, wherein said switch means further comprises activating means located at the long-turn of said bend for cooperation with said sensing and deactivating means for maintaining said withdrawal means in an activated state in the absence of yarn within said bend.

6. A device as in claim 5, wherein said sensing and deactivating means is in the form of a photoreceiver switch and said activating means is in the form of a photoprojector, and wherein said photoprojector and photoreceiver cooperate through a light beam extending therebetween within said bend to maintain said withdrawal means in an activated state in the absence of yarn therebetween.

7. A device as in claim 4, wherein said sensing and deactivatingmeans comfprises yarn aligning means or aligning yarn within said internal pathway and at said bend adjacent said short-turn thereof and sensing and switching means for sensing said aligned yarn and for deactivating said withdrawal means. 8. A device as in claim 7, wherein said yarn aligning means includes a bifurcate yarn collating element having opposing yarn receiving arms meeting in an apex portion, said arms opening into the interior of said conduit bend, whereby yarn withdrawn from said supply and through said conduit means is received between said arms and aligned adjacent said. apex.

9. A method for detecting a predetermined length of yarn comprising moving said yarn through a conduit having a predetermined enclosed internal pathway including a fixed bend, and a second fixed bend therein,

aligning said yarn adjacent and within the short-turn of said bend, and

detecting the presence of said yarn so aligned,

whereby the length of yarn within said conduit to and around said second bend is of said predetermined length.

10. A method as in claim 9, wherein said moving and said aligning is by air currents moving in the same direction as said yarn moving and said detecting is by photoelectric means.

Patent No., 3,728,550 Dated April '17, 1.973

Inventor) Luther A. Clelond, Jr. and Albert D. Hermon It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

On the cover sheet, "Attorney-Donald H. Feldman should read M Agent-Donald H. Feldman Column 1, line 66, "mechanism" should read meohanisms 1 Column 5, line 9, "for should read from and "a" should read as line 26, "portion" should read portions and line 57,, length, and then add" should read length, and (c) igned sealed this 22nd day of January 19m.

(SEAL) Attest:

EDWARD MFLETCHER,JR, I T RENE D. TEGTMEYER Attesting Officer Acting Commissioner of Patents 

1. A device for the withdrawal of a predetermined length yarn from a supply thereof, comprising: conduit means for establishing an enclosed, internal pathway of predetermined length for said withdrawn yarn, said means having an entry for receiving yarn from said supply, a fixed bend at a predetermined distance from said entry and a second fixed bend beyond said bend; yarn withdrawal means for withdrawing yarn from said supply through said pathway and adjacent the short-turn of said bend; and switch means, located at least in part within said enclosed internal pathway adjacent said short-turn, for sensing the presence of yarn thereat and deactivating said withdrawal means thereupon; wherein, said predetermined yarn pathway is established from said entry to and around said short-turn and to and around said second bend.
 2. A device as in claim 1, wherein said bend and second bend are joined by a linear portion of said conduit, and have upstream and downstream thereof, respectively, conduit portions which are substantially linear, and wherein the axes of said upstream and intermediate portions and of said intermediate and downstream portions are set at, respectively, a turn-through angle to one another of at least 45*.
 3. A device as in claim 2, wherein said turn-through angle of said two sets of axes is substantially 90*.
 4. A device as in claim 1, wherein said switch means comprises sensing and deactivating means located at the short-turn of said bend for photoelectric sensing of the presence of yarn within said bend and for deactivating said withdrawal means.
 5. A device as in claim 4, wherein said switch means further comprises activating means located at the long-turn of said bend for cooperation with said sensing and deactivating means for maintaining said withdrawal means in an activated state in the absence of yarn within said bend.
 6. A device as in claim 5, wherein said sensing and deactivating Means is in the form of a photoreceiver switch and said activating means is in the form of a photoprojector, and wherein said photoprojector and photoreceiver cooperate through a light beam extending therebetween within said bend to maintain said withdrawal means in an activated state in the absence of yarn therebetween.
 7. A device as in claim 4, wherein said sensing and deactivating means comprises yarn aligning means for aligning yarn within said internal pathway and at said bend adjacent said short-turn thereof and sensing and switching means for sensing said aligned yarn and for deactivating said withdrawal means.
 8. A device as in claim 7, wherein said yarn aligning means includes a bifurcate yarn collating element having opposing yarn receiving arms meeting in an apex portion, said arms opening into the interior of said conduit bend, whereby yarn withdrawn from said supply and through said conduit means is received between said arms and aligned adjacent said apex.
 9. A method for detecting a predetermined length of yarn comprising moving said yarn through a conduit having a predetermined enclosed internal pathway including a fixed bend, and a second fixed bend therein, aligning said yarn adjacent and within the short-turn of said bend, and detecting the presence of said yarn so aligned, whereby the length of yarn within said conduit to and around said second bend is of said predetermined length.
 10. A method as in claim 9, wherein said moving and said aligning is by air currents moving in the same direction as said yarn moving and said detecting is by photoelectric means. 